Twitter announced its partnership with Vine, a video-sharing app that posts six-second videos onto a tweet, on Thursday, Jan. 24. Marie McGrory/NPR hide caption

itoggle caption Marie McGrory/NPR

President Obama and House Speaker John Boehner on Nov. 16. Carolyn Kaster/AP hide caption

itoggle caption Carolyn Kaster/AP

Investors and financial analysis firms are increasingly looking at "sentimental analysis" — such as Facebook "likes" and Twitter messages — to gauge a company's social popularity. iStockphoto.com hide caption

itoggle caption iStockphoto.com

A young boy works at an illegal gold mine in Dareta, Nigeria. David Gilkey/NPR hide caption

itoggle caption David Gilkey/NPR